1. Field of the Invention
The present invention relates to a cleaning sheet which is intended to be used for cleaning a floor surface or the like when attached to a cleaning head of a mop-like cleaning device, and more particularly to a cleaning sheet which is resistant to slipping relative to a bottom face of the cleaning head.
2. Description of the Related Art
There have been known cleaning sheets which may be used for cleaning the house floor when attached to a cleaning head of a mop-like cleaning device. Such conventional cleaning sheets are typically constructed of a single nonwoven fabric or by layering two or more nonwoven fabrics on top of one another and used in a dry state or in a wet state with water or detergent contained in a liquid absorbent layer. Moreover, they are preferably disposable and easy to attach to and detach from the cleaning head of the cleaning device.
Japanese Examined Patent Publication No. S62-013008 discloses a loop tape of a Velcro fastener secured on either a cleaning head or a cleaning member to be attached to the cleaning head and a hook tape of the Velcro fastener secured on the other.
Japanese Utility-Model Registration No. 2507300 discloses retainers which are slashed sheets and disposed on a top face of a cleaning head. By tucking a part of a cleaning sheet into cuts of the retainers, the cleaning sheet can be retained on the cleaning head.
Japanese Unexamined Patent Publication No. H09-187411 discloses clamp members pivotally mounted on a top face of a cleaning head. By clamping a part of a cleaning sheet between the clamp members and the cleaning head, the cleaning sheet can be retained on the cleaning head.
Japanese Unexamined Patent Publication No. H09-075284 discloses a pressure-sensitive adhesive layer (or sticky layer) disposed on a bottom face or top face of a cleaning head for retaining a cleaning sheet on the bottom face.
In the invention disclosed in Patent Publication No. S62-013008, either of the loop tape and the hook tape must be provided on the cleaning sheet for enabling the use of the Velcro fastener. However, if the cleaning sheet is designed to be thrown away after use (or disposable), providing the loop/hook tape on the cleaning sheet will raise the cost.
On the other hand, the mechanisms disclosed in Utility-Model Registration No. 2507300 and Patent Publication No. H09-187411 are suitable for use with a disposable cleaning sheet. Here, the cleaning sheet is retained such that its central portion is laid on the bottom face of the cleaning head and its side portions are folded back and secured on the top face of the cleaning head. However, in the case where only the side portions of the cleaning sheet are secured on the cleaning head, the central portion of the cleaning sheet, which is laid on the bottom face of the cleaning head, tends to slip and shift by the friction between the cleaning sheet and the floor surface or the like during cleaning.
In order to prevent slipping between the cleaning head and the cleaning sheet, the bottom face of the cleaning head may be made of a material having a relatively high coefficient of friction such as urethane foam resin, but even in this case, it is still difficult to prevent slipping between the cleaning head and the cleaning sheet if the frictional resistance between the cleaning sheet and the floor surface is high.
On the other hand, the pressure-sensitive adhesive layer disclosed in Patent Publication No. H09-075284 is not practical because its adhesion decreases with the passage of time and also by dirt or dust adhering to the pressure-sensitive adhesive layer.